package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.core.toolkit.BeanUtils;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.concurrent.TimeUnit;
import java.util.stream.Collectors;

import static com.hmdp.utils.RedisConstants.*;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {
    @Resource
    private IBlogService blogService;
    @Resource
    private IUserService userService;
    @Resource
    private CacheClient cacheClient;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private IFollowService followService;

    /**
     * 查询当前登录用户收件箱的笔记
     * @param max
     * @param offset
     * @return
     */
    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) {
        // 1.获取当前用户
        Long userId = UserHolder.getUser().getId();
        // 2.查询收件箱 ZREVRANGEBYSCORE key Max Min LIMIT offset count
        String key = FEED_KEY + userId;
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key, 0, max, offset, 2);
        // 3.非空判断
        if (typedTuples == null || typedTuples.isEmpty()) {
            return Result.ok();
        }
        // 4.解析数据：blogId、minTime（时间戳）、offset
        List<Long> ids = new ArrayList<>(typedTuples.size());
        long minTime = 0; // 2
        int os = 1; // 2
        for (ZSetOperations.TypedTuple<String> tuple : typedTuples) { // 5 4 4 2 2
            // 4.1.获取id
            ids.add(Long.valueOf(tuple.getValue()));
            // 4.2.获取分数(时间戳）
            long time = tuple.getScore().longValue();
            if(time == minTime){
                os++;
            }else{
                minTime = time;
                os = 1;
            }
        }
        os = minTime == max ? os : os + offset;
        // 5.根据id查询blog
        String idStr = StrUtil.join(",", ids);
        List<Blog> blogs = query().in("id", ids).last("ORDER BY FIELD(id," + idStr + ")").list();

        for (Blog blog : blogs) {
            // 5.1.查询blog有关的用户
            queryBlogUser(blog);
            // 5.2.查询blog是否被点赞
            isLikeBlog(blog);
        }

        // 6.封装并返回
        ScrollResult r = new ScrollResult();
        r.setList(blogs);
        r.setOffset(os);
        r.setMinTime(minTime);

        return Result.ok(r);
    }

    /**
     * 保存探店博文，并通过feed流推送到粉丝收件箱
     * @param blog
     * @return
     */
    @Override
    public Result saveBlog(Blog blog) {
        //1. 获取登录用户
        UserDTO user = UserHolder.getUser();
        blog.setUserId(user.getId());
        //2. 保存探店博文
        boolean isSuccess = blogService.save(blog);
        if (!isSuccess){
            return Result.fail("新增探店笔记失败");
        }
        //3.实现推送到粉丝收件箱
        //3.1 查询当前登录用户的所有粉丝
        List<Follow> follows = followService.query().eq("follow_user_id", user.getId()).list();
        //3.2 推送到粉丝收件箱
        follows.forEach(follow -> {
            //3.2.1 获取粉丝的id
            Long userId = follow.getUserId();
            //3.2.2 推送
            stringRedisTemplate.opsForZSet().add(FEED_KEY + userId,
                    blog.getId().toString(), System.currentTimeMillis());
        });
        // 4.返回id
        return Result.ok(blog.getId());
    }
    @Override
    public Result likeBlog(Long id) {
        //1. 获取当前登录用户
        Long userId = UserHolder.getUser().getId();
        //2. 获取redis的key
        String key = CACHE_BLOG_LIKED_KEY +id;
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        //3.判断是否点赞过
        if (score == null){
            //3.1 未点赞过 --> 允许点赞
            boolean isSuccess = update().setSql("liked = liked + 1").eq("id", id).update();
            if (isSuccess){
                stringRedisTemplate.opsForZSet().add(key, userId.toString(),System.currentTimeMillis());
                //点赞信息发生变化，删除缓存
                stringRedisTemplate.delete(CACHE_BLOG_KEY + id);
            }
        }else{
            //3.2 点赞过 --> 允许取消点赞
            boolean isSuccess = update().setSql("liked = liked - 1").eq("id", id).update();
            if (isSuccess){
                stringRedisTemplate.opsForZSet().remove(key, userId.toString());
                //点赞信息发生变化，删除缓存
                stringRedisTemplate.delete(CACHE_BLOG_KEY + id);
            }
        }
        return Result.ok();
    }

    /**
     * 查询博客点赞列表前5
     * @param id
     * @return
     */
    @Override
    public Result queryBlogLikes(Long id) {
        //1. 获取redis的key
        String key = CACHE_BLOG_LIKED_KEY + id;
        //2. 查询top5的点赞用户 zrange key 0 4
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        if (top5 == null || top5.isEmpty()){
            //3 如果为空，返回一个空的集合
            return Result.ok(Collections.emptyList());
        }
        //4. 解析用户id
        List<Long> ids = top5.stream().map(Long::valueOf).collect(Collectors.toList());

        //5. 把ids转为string类型接入到sql语句
        String idStr = StrUtil.join(",", ids);

        //6. 根据id查询用户 WHERE id IN ( 5 , 1 ) ORDER BY FIELD(id, 5, 1)
        List<UserDTO> userDTOS = userService.query()
                .in("id", ids).last("ORDER BY FIELD(id," + idStr + ")")
                .list().stream().map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());
        return Result.ok(userDTOS);
    }



    @Override
    public Result queryHotBlog(Integer current) {
        // 根据用户查询
        Page<Blog> page = blogService.query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();
        // 查询
        records.forEach(blog -> {
            //查询是否点赞过
            this.isLikeBlog(blog);
            //查询当前登录用户
            this.queryBlogUser(blog);
        });
        return Result.ok(records);
    }

    /**
     * 判断当前登录用户是否点过赞
     * @param blog
     */
    private void isLikeBlog(Blog blog) {

        //1. 获取当前登录用户
        UserDTO userDTO = UserHolder.getUser();

        if (userDTO == null){
            //用户未登录，无需查询
            return;
        }
        Long userId = userDTO.getId();
        //2. 获取redis的key
        String key = CACHE_BLOG_LIKED_KEY + blog.getId();
        //3. 判断是否点赞过
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        blog.setIsLike(score != null);

    }

    @Override
    public Result queryBlogById(Long id) {
        //1.  从redis查询缓存
        Blog blog = cacheClient.queryWithPassThrough(CACHE_BLOG_KEY , id, Blog.class,this::getById,CACHE_BLOG_TTL, TimeUnit.MINUTES);
        if (blog == null){
            return Result.fail("文章不存在");
        }
        //2.查询数据库
        queryBlogUser(blog);

        //3. 查询当前用户是否点过赞
        isLikeBlog(blog);

        return Result.ok(blog);
    }

    private void queryBlogUser(Blog blog) {
        User user = userService.getById(blog.getUserId());
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
    }

}
